Process of making concavo-convex glass plates.



m. 643,223. Patented Feb. I3, moo.

- c. DHE & L. HUUZE.

PROCESS OF MAKING CUNCAVO-CUNV-EX GLASS PLATES.

(Application filed Apr. 17, 1899.)

(No Model.)

INVENTOHS' W/ TN E SSE S ATTORNEY.

mares nirrnn PROCESS OF MAKING CONCAVO-CONVEX GLASS PLATES.

SFECIFICATION forming part of Letters Patent N0. 6 4=3,223, datedFebruary 13, 1900. Application filed April I7, 1899- Serial No. 713,240.(No specimens.)

To aZZ whom it may concern.-

Be it known that we, CHARLES DHE and LUO I-IOUZE, citizens of the UnitedStates, residing atI-Iartford City,in the county of Blackford and Stateoflndiana, have invented a certain new and useful Process for MakingConcave-Convex Glass Plates, of which the following is a specification.

In the drawings, Figure l is a cross-section through the middle of thesheet. Fig. 2 is a cross-section through the middle of the sheet atright angles to the section shown at Fig. 1. Fig. 3 is a top view of arectangular supporting-frame with a sheet of glass resting on it inplace. Fig. 4c is a top view of a supporting-frame adapted for theformation of two oval concave surfaces and two circular concave'surfaeeson one sheet of glass. Fig. 5 is a detail View showing a portion of thesupporting-framein section.

Similar numerals of reference refer to similar parts throughout theseveral views.

Asheet of glass 5 is formed into one or more concave-convex surfaces 6,with a fiat surface or margin 7 surrounding said surfaces, the curvedportions commencing at all points of such margin. The areas of suchconcavoconvex surfaces may be oval, circular, rectangular, or otherdesired form.

The process is as follows: We take a sheet of plate-glass or a planesheet of glass-such as is furnished by glass-makers for windows,picture-frames, and like purposes-and we place it upon asupporting-frame 8, preferably of iron. The supporting-surfaces of thissupporting-frame are adapted to correspond with the form of marginsdesired. In Figs. 1, 2, and 3 it is a rectangular form, the marginintended to be about one and one-quarter inches wide. The sheet of glassis placed upon this frame and it is then placed in afurnace. As soon asthe glass begins to become soft its edges will curl up more or less; butupon being further heated they will fall flat again upon themarginalsupport of the frame. At this moment we place on top of theframe weights 9 to hold the margin or margins 7 in such a position. Forthis purpose we prefer a weighting-frame of exactly the same size as thesupporting-frame and of suitable weight, which is let down on the sheetof glass covering the marginal surfaces. The weights or weighting-framebeing subjected to the same heat from the beginning of the process, theapplication of the heat is then continued until the glass becomes sosoft that it begins to fall Within the margin or margins, formingconcavo-convex surfaces of given areas by its own weight, a rectangularframe being shown by the cross-sections in Figs. 1 and 2. As soon as theconvexed or concaved glass has reached the limit of curvature desired Wemove the frames,with their sheet of glass,into a cooling compartment,thereby arresting further descent of the glass and fixing it in the formdesired. Such limit maybe ascertained by the inspection of the operator,or a mold may be placed under the sheet which will regulate the same andlikewise adjust the form of the curvature, if desired. The glass is thenannealed as commonly done in window-glass manufacture. As soon as theglass hardens so as to keep its shape the weights or weighting-frame areremoved to prevent any fracture. It is obvious that by the use of aframe of properconstruction and. Weights or weighting-frame holding theflat or marginal portions of the sheet in proper position we can formconcave-convex portions of different shapes in area than the oneillustrated in Figs. 1, 2, and 3, and such shapes may be oval, circular,or other form in area, and may be on different portions of one sheet. Bythis means a great variety of such concave-convex surfaces can be formedand on a single sheet of glass. We have illustrated in Fig. 4 a framefor forming two oval and two circular parts on one sheet, whereby suchconvex surfaces will be formed as. stated. This process of reheating theglass and forming these surfaces will give the treated glass a lusteradditional to that it formerly had and strengthen the glass, and it isalso obvious that if the convex surface is opposed to the direction fromwhich injuries or blows or pressure shall come such glass when securedin a holding-frame will be much stronger than a plane sheet of glass ofthe same thickness.

Having thus described our invention, we claim- The process of formingconcavo-convex glass plates, which consists in first supporting a glassplate around the margins of the ther descent of the glass, and fixing itin the desired formation, subjecting the same to form desired.

heat, thereby softening the glass and causing In witness whereof we havehereto set our the same to curl up at the marginal edges of i hands, inthe presence of two witnesses, this 15 5 the formation, continuing theheat, thereby 12th day of April, 1899.

causing the said edges to become again flat,

then holding the said marginal edges in position by heated pressurethereon, continuing the heat, until the glass Within the margin to fallsto the desired curvature, then cooling the same so supported, therebyarresting fur- CHARLES DI-IE. LUO HOUZE.

Witnesses:

S. B. FLEMING, HENRY SPALDING.

